implantation bleed or AF on clomid 2?

💞SuE💞 • 39/ TTC#1 4 rounds of clomid at 25mg. 1 round of ivf/fet failed dec16. 2nd round fresh failed 14feb17. fet in april17
just finished a clomid 2nd round and it's day 27 and I had blood in my pants. Hopes dashed, been so upset. everything was right... I felt ovulation pain on cd14 and baby danced everyday and twice on ovulation day, and it seemed unfair to see AF today. however it's been 8 hours and the blood hasn't thickened, it's not like a normal period at all, but this time it should be so heavy. the colour is a little staler too... is this implantation bleeding? or a period? I'm supposed to take clomid days 2-5 and how can I if I'm pregnant. Will speak to the doctor tomorrow  but they make me feel dumb when it seems that I don't even know my periods properly. I'm so confused! I don't want to miss a cycle by not taking my clomid as my pcos causes long cycles and I'm already 38. help me! any advice on this????